1. Field of the Invention
The present invention relates generally to a tape loading device for a magnetic recording and/or reproducing apparatus, such as, video tape recorder (VTR) or the like, and more particularly is directed to an improved tape loading device of the so-called U-loading type for use in a cassette-type helical scan VTR.
2. Description of the Prior Art
As is well known, a tape loading device for a cassette-type helical scan VTR may comprise a support ring rotatable about the rotary head drum and carrying a plurality of tape guides spaced apart along the ring and being effective, upon rotation of the support ring, to withdraw magnetic tape from a cassette suitably mounted apart from the drum and to wind or wrap the withdrawn tape about a portion, for example, approximately a 180.degree. extent, of the circumferential surface of the rotary head drum. In order to achieve helical disposition of the tape wrapped about the rotary head drum, the support ring of the tape loading device is rotated in a plane which is inclined in respect to the usually horizontal plane containing the longitudinal median of the tape within the mounted tape cassette. By reason of such inclination of the plane of rotation of the support ring, the magnetic tape initially drawn horizontally out of the cassette by the tape guides on the ring is gradually lowered as it is helically wrapped about a portion of the circumferential surface of the rotary head drum. At its lowermost level, the tape is diverted or escapes tangentially from the surface of the drum for engagement with the capstan adapted to longitudinally drive the tape, and then the path of the tape is reverted for return of the tape to the cassette along a gradually rising course which eventually reaches the level of the mounted cassette.
In the usual tape loading device of the above described type, the tape guides provided on the support ring are fixed to the latter at successively different predetermined angles relative to the plane of rotation of the ring so that the tape withdrawn from the cassette and engaged by the plurality of tape guides on the support ring is sequentially twisted by the tape guides. Due to the sequential twisting of the tape in the course of its engagement by the plurality of tape guides fixed on the support ring at respective different angles relative to the latter, the sliding friction between the tape and the tape guides give rise to a relatively large resistance to the movement of the tape. Such large resistance to movement of the tape results in irregular travel of the tape and frequently in damage or creasing of the latter.